


Unforgivable

by ashal_telsu



Category: Harry Potter - J. K. Rowling, Sherlock (TV), Sherlock Holmes & Related Fandoms
Genre: Alcohol Abuse/Alcoholism, Alternate Universe - Canon Divergence, Alternate Universe - Different First Meeting, Alternate Universe - Harry Potter Setting, Angst with a Happy Ending, Cruciatus Curse, Drug Use, Exchangelock AU Exchange 2014, Fluff and Angst, M/M, Minor Character Death, both are not explicit and only shortly mentioned, but in case it is a trigger for anyone, exchangelock, this is pretty fluffy until it gets angsty
Language: English
Status: Completed
Published: 2014-07-11
Updated: 2014-07-11
Packaged: 2018-02-08 08:27:37
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 3
Words: 7,094
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/1933929
Author URL: https://archiveofourown.org/users/ashal_telsu/pseuds/ashal_telsu
Summary: <blockquote class="userstuff">
              <p>“You said you were in love with her.”<br/>“I know, but you are more important to me than any girl in the entire world,” John said, taking Sherlock’s hand and gently squeezing it. “And no one is going to change that.”</p><p>Sherlock and John grow up together in a small Wizarding Town. They go to Hogwarts together, and eventually they fall in love. But when John experiences tragic loss during the famous Battle of Hogwarts, they both turn to other comforts, their problems escalating in an event that drives them apart and makes John join the army. Until a bullet brings him home and they meet at Bart's over a decade later.</p><p>This was written for the Exchangelock AU exchange.</p>
            </blockquote>





	1. Imperio

**Author's Note:**

  * For [LacieRiverPanda27](https://archiveofourown.org/users/LacieRiverPanda27/gifts).



> Just a quick note regarding the timeline: I tried to sort of follow both the BBC Sherlock Canon and the Harry Potter Canon. And started by looking up rough dates of birth. So basically, Sherlock is one year older than Harry Potter, and John is three years older than Harry Potter. Making the age difference between them two years.

John was walking swiftly away from Bart’s, wondering how it had come to this. It had been over a decade since he saw him last, Sherlock was back in his life. Saying that it was a shock was an understatement. Sherlock had barely aged, he still had those angelic features John fell in love with when he was younger. Seeing him there in a muggle lab was strange, but somehow it made sense. Sherlock always had a fondness for muggle sciences, and it was only natural for him to get bored of the wizarding world after a while. What do you say to your former boyfriend after you haven't seen him in so long? To your former best friend? To the man you hurt unforgivably when you were drunk and stricken with grief?

John had left without a word. He shoved the memories back into a drawer in his mind, just like the pieces of his wand and his old scarf were stuffed in a drawer in his desk. The desk in the very bedsit he was staying in, the tiny place he could barely afford with his army pension. He had nowhere else to go. Nothing felt like home to John without magic. Especially after he had sworn never not to use it after the incident.

But maybe he could now, with Sherlock. Start anew. It was a comforting thought.

 

Silverkeep was an old and rather large town, and yet it couldn't be found on any England map. If you asked someone who lived nearby how to get there, they would look at you curiously and tell you that there was no town with that name anywhere within a radius of fifty kilometres. It wasn’t deserted either, yet a stranger would see nothing but ruins if they happened to come across it. Silverkeep was a wizarding town, protected from the eyes of unknowing muggles thanks to powerful and ancient protection spells. But that didn't mean that there weren't any muggles living there. It was a large town, perfect for half-blood families who wanted their children to grow up without having to hide their magical abilities. This very town was the place a young boy named John Watson grew up.

John was a half-blood, which in the wizarding world is meant only one of the parents were a wizard. His mother was a muggle and his father was a wizard. Life was easy for John's younger sister and himself. They made friends with ease and even thought John never had really close friends, he was happy.

Coming from what was easily the embodiment of the stereotypical Slytherin pure-blood family, Sherlock was an incredibly smart and bright child. Almost too intelligent for his own good. His head was always filled with details he couldn’t blend out, and became restless when it wasn’t stimulated enough.

On the day Sherlock and John met for the first time, the sun was shining without mercy. Sherlock had once again insulted, or deduced as Sherlock preferred to say, his classmate Harry Watson to tears. This time John happened to see, he was angry as the eye could see. He rushed over to her, "Why did you do that?” he yelled, and just like that Sherlock was lying in the sand, drenched in ice cold water. Everyone around them was quiet. The young boy with curly hair was famous for his outburst, and this was the most interesting thing that had happened all week. But then something peculiar happened: Sherlock giggled, grinning up at the blond. “Not bad for a half-blood. I can see why you’re the favourite child,” he said, standing up and shaking his head out, sending droplets of water flying everywhere. “But seriously, that cleared my head. Harriet, I'm sorry for saying that you stole Mrs Peters chocolate frogs. It was obviously your brother who did it for a dare.” John gaped at the tiny boy before stuttering out a “That was brilliant.” And because that’s just the way things work when you are young, Sherlock and John became best friends that day.

 

"Are you excited for Hogwarts?" John and Sherlock were lazing about in John's room to avoid Mummy Holmes who was overcome with excitement that her  baby was all grown up and old enough for Hogwarts, enjoying their ice lollies and talking about school.

"Excited? Yes, very much," Sherlock replied, grinning at his best friend. "But mostly because I can't stand staying here any longer. I want to learn proper magic, just like you. And I want to be allowed to use my wand. What does Mummy think I'll do, blow up the house?"

John snorted. "I know you well enough to say that that is a very real possibility. Remember how long it took to regrow your eyebrows when you decided to try out the Incendio spell? I received an hour-long lecture about why it was a bad idea to give you a spellbook."

Giggling, Sherlock poked out his tongue at John. "Well, I was curious if it would work even without a wand," he argued. "Anyway, I might not see you as often as we hoped. You're a Hufflepuff and I am most likely going to be a Slytherin. Mycroft told me about the differences between the houses." Sherlock didn't really want to be the reason why John was ridiculed for being friends with the enemy.

"Since when do you care about house differences? And besides, I'm only in year three- Oh." John's smile dropped when he saw Sherlock's expression. It was true, the tensions between the two houses were incomprehensively high, but John wouldn't let that destroy his friendship with the single most interesting person on the entire planet. "Sherlock, I swear to Godric that no one is going to say anything. And if they do, I'll just hex them. I may not be wearing a red and golden scarf, but that doesn’t mean I'm a coward. Now, did you decide what pet you want to have yet?"

"I'm getting a screech owl just like the one you have," Sherlock told him excitedly, easily distracted by John's reassurances. "I thought it would be nice for Flaps to have a friend, you know?"

John smiled, just as excited as Sherlock that they were going to see each other every day from now on. "You know what, I think that's brilliant."

The rest of summer passed faster than the two of them liked, they went shopping together in Diagon Alley and had some of Florean Fortescue’s ice cream afterwards. They spent a lot of time at the lake near John’s house as well; John read under the shadow of the trees while Sherlock collected samples of everything he could possibly find.

 

The ride on the Hogwarts Express had passed quite amiably and Sherlock had even nodded off after a while, leaning against John’s shoulder. Eventually they had to part ways though and Sherlock looked at John with a mixture of nervousness and excitement, who grinned back at him.

Sherlock usually wasn’t a fan of big ceremonies, nor did he believe that there were moments in one’s life that unchangeably determined one’s future, but even he had to admit that the sorting ceremony was a turning point in his life. Taking a deep breath, Sherlock pulled himself together and walked over to the stool when his name was called out. He sat down, his feet dangling a bit in the air, and then the woman who had introduced herself as Professor Sprout put the hat on his head.

“Oh, another Holmes,” the Sorting Hat mumbled quietly to itself. “I could make the obvious choice and put you into Slytherin like the rest of your family, but you don’t care about ambition, do you? There is always a lot going on in your head and you’re eager to learn, so this is an easy choice to make… Ravenclaw!” Sherlock, baffled because he had been so sure that he would be sorted into Slytherin, looked towards the Slytherin table at his brother, afraid that he somehow did something wrong, but Mycroft merely smiled and clapped his hands. And John was beaming at him, obviously proud of him.

Sherlock thoroughly enjoyed being at Hogwarts, even though he didn’t see John as often as he liked. But they studied together, either in the library or in the Hufflepuff Common room. (They tried to study in Sherlock’s common room once, but John stood in front of the door for the good part of an hour trying to figure out the solution to the riddle before he eventually gave up.) There were a lot of subjects Sherlock liked and some he didn’t like at all, but John usually made it interesting to learn for them. Sherlock never had problems with homework and was able to help John with his sometimes, he often read John’s books when he was bored and never deleted the information from his mind palace.

They settled into a comfortable routine, having breakfast together (no one batted an eye at Sherlock when he sat down with John at the Hufflepuff table) then they walked together to their classes, ate lunch together, and spent the rest of the afternoon studying or just walking around on the grounds. Sherlock liked to take samples from the Forbidden Forest or the Great Lake, and John liked to watch the Quidditch practices. John had other friends but most of the time he was with Sherlock. Some people wondered why they spent so much time together. Sherlock used the time he didn't spend with John on his experiments. Every now and then, John would bring him sweets or new flasks from his trips to Hogsmeade.

Then John met Sarah. They both had Potions and DADA together. She became his girlfriend after he fell for her when she would make him laugh with her awful puns. Sherlock hated her. They were only thirteen, so the furthest they went was holding hands and the one time John kissed her cheek, but Sherlock hated seeing it. He told himself that he just didn’t want John to waste his valuable time on someone so unimportant, but he couldn’t deny that there was a tingly feeling in his stomach when he saw the way John smiled at her. 

“Sarah said I'm spending too much time with you,” John told Sherlock one day while sitting by the lake. “She thinks that I should focus more on her because she’s my girlfriend.”

“Oh,” Sherlock said, simply because he had nothing else to say.

“Yeah.”

“I wanted to study more anyway, so this is rather convenient.”

“I broke up with her.”

Sherlock frowned, but he couldn’t help but feel satisfied that John liked him more than Sarah. And maybe he was also a little bit smug because his plan, namely asking John for help whenever John had intended to go on a date, had worked. “You said you were in love with her.”

“I know, but you are more important to me than any girl in the entire world,” John said, taking Sherlock’s hand and gently squeezing it. “And no one is going to change that.”

 

It was the Christmas Eve during Sherlock’s second year at school. The Watsons were as always invited to the Holmes’ Christmas party, and Sherlock and John were even allowed some alcohol to celebrate Sherlock’s first year at Hogwarts. Mummy Holmes was incredibly proud of both her sons, Mycroft had managed to get an internship with the ministry and Sherlock had an ‘Outstanding’ in almost all of his classes.

After dinner Sherlock and John snuck away to Sherlock’s room for their presents, each with a glass of eggnog. Sherlock had gotten John a book about Quidditch that year and a couple of cassettes for the strange but intriguing VHS player John’s mother had bought. John gave Sherlock his present with the warning to be careful with it and started looking through the films to decide which they should watch during the rest of the holidays and which they should keep for summer.

“What is it?” Sherlock asked, examining his present from all sides.

“You remember how I told you about the muggle sciences that is similar to potions? Chemistry and biology? Well, with this thing you can look at cells and everything really close, and all without magic. It’s called a microscope.”

Sherlock was already unpacking it and reading the instructions. “And it’s true what it says here? That you can look at things like through an extremely strong looking glass?”

“Yup. My cousin has one, she showed me what my hair and all that looks like close up. I thought you might like it.”

“This is incredible,” Sherlock said, overcome with childish joy. “Why have I never heard of something like this? Think of all the experiments I can make with this. I can directly look at what happens when I apply magic.”

“So I take it you like your present, then?”

Instead of answering, Sherlock just wrapped his arms around John and kissed his cheek, overcome with excitement. Later that night when all the guests were gone, he lay awake in his room, thinking about how soft John’s cheek had been and there it was again, that warm fuzzy feeling in his stomach. Maybe he had a little bit too much to drink.

 

It wasn’t until well into his fifth year at Hogwarts that John got another girlfriend. This time her name was Jeanette and she was a Ravenclaw as well. Sherlock wanted to hate her because she was taking away his time with John, but he couldn’t deny that John smiled more. And he couldn’t drive her away like he did with Sarah, not without driving John away too. Sherlock was sitting in the small pub in Hogsmeade where he and John had agreed to meet to study. Except that they apparently wouldn’t, because John was already one hour late and he was probably somewhere with Jeanette, snogging like the teenagers they were. Sherlock thought back to the day at the lake where John had told him that Sherlock was more important than every girl and wondered what had changed since then. The last time Sherlock had tried to keep John away from his date the blond had gotten really annoyed and warned Sherlock not to play that game again.

“Sherlock, I swear. If you try to do this one more time, by Merlin’s beard, I won’t talk to you for a month.”

“But John I need your help. Seriously. If I don’t get those plants tonight they-“

“Shut it. I have a date tonight and I don’t care if your stupid plants only bloom once every ten years. Ask someone else or do it alone.”

Sherlock just stared at him with that broken look that made him seem so innocent and sad and John sighed, pulling Sherlock in his arms. “I'm sorry, I shouldn’t have lashed out, it was uncalled for. It’s just, I really like Jeanette and this is special. I swear I'll be there next time.”

“You said I was more important than stupid girls! I should have known that you’d desert me in the end to run off with your stupid, cheating girlfriend. Oh, did I spill the secret? Your precious and perfect girlfriend regularly makes out with a Slytherin boy in a potions classroom. Just look at her robes, Snape would never allow a student to sit on the tables.” He left without pointing out that the next time poisonous nymph lilies bloomed would be in thirty years, and ignored churning in his stomach.

They broke up eventually over something awfully tedious and Sherlock tried not to be too relieved that he had John for himself again. Especially now that there was apparently a bloodthirsty monster roaming the halls of Hogwarts with the intent to rid the school from all muggle blood. Sherlock wouldn’t put it past John to jump between Jeanette and the monster if they happened to come across it while they were out. And the mere thought of losing John forever hurt more than Sherlock was willing to admit.


	2. Avada Kedavra

Sherlock had read about dementors, of course. But he never thought that he would ever see one, let alone so many at Hogwarts.  It was cold when they went through the train in the middle of nowhere, and it was even colder when they got out and to the carriages. John took his hand and squeezed it tightly when Sherlock shivered. He instantly felt a little warmer and his cheeks turned pink.

Apparently there was a prisoner from Azkaban on the loose, he was after that Potter kid. John told Sherlock that the boy was the new star in Hufflepuff, together with his friends and the Weasley kids. Sherlock wondered why no one had expelled him yet, he seemed to be a magnet for trouble and was seriously disrupting his time at Hogwarts.

John became a Quidditch player for the Hufflepuff team that year, a chaser, and with that Sherlock’s interest in the game rose exponentially. John was absolutely marvellous at being a chaser. Sherlock didn't really care for the sport, but he could spend hours watching John fly around. He quickly learned that he could cheer for whomever he wanted unless Ravenclaw was playing. Sherlock attended each of John’s games and most practices.

John didn’t have a girlfriend that year, and if Sherlock was honest he would admit that it might be because most girls thinking about flirting with John thought the blond had a long-term muggle girlfriend. Sherlock had nothing to do with that, of course. All he did was tell someone about John’s cousin and the girls he always hung out with, if they came to wrong conclusions then it wasn’t Sherlock’s fault and entirely not on purpose.

The year passed quite uneventful except for a few incidents with dementors, and then of course what John and other students secretly called “the big sleepover,” because that was basically what followed the break-in to the Quidditch common room. Sherlock wanted to go and investigate, but John told him not to meddle with a ruthless killer. Seeing the worry on his best friend’s face, Sherlock finally gave in and promised to leave it alone. The best part of the sleepover was that the teachers didn’t really care about houses and no one batted an eye at him when Sherlock rolled out the small mattress next to John’s, lying on his side.

“Are you scared?” John whispered when the candles were out and the Great Hall mostly quiet. There was still a slimmer of light coming through the windows and no teacher said anything about the quiet whispers.

Sherlock considered his answer. He wasn’t really scared about himself, that Black person had shown no interest whatsoever in Ravenclaws, but he did break into John’s common room.

“A bit. I don’t want anything to happen to you.”

John scooted a little bit closer so that their faces were not more than a few inches apart. Sherlock could feel John’s breath on his face and his heart started beating faster, a loud pounding in his ear. They had shared a bed before during their sleepovers back at home, but this was different somehow and Sherlock couldn’t place his finger on what it was. John was so close that Sherlock could count the freckles on his nose, but he couldn’t stare at anything but John’s soft lips. The teen nearly flinched when something touched his hand, but it was only John, entwining their fingers with a grin.

“I'll keep you safe,” John promised, and Sherlock feel asleep with the thought that John’s breath smelt like vanilla candy broomsticks.

 

 “I'll definitely get an O in DADA and Charms. And I'm pretty sure I'll get an E in Herbology. So what you have to help me with is Potions and Transfiguration.”

They were sitting at breakfast a good week into John’s final year at Hogwarts. It definitely promised to be an exciting year, he and Sherlock were both excited for their exams that year, Sherlock would take his O.W.L.s and John his N.E.W.T.s, and he hoped to be good enough to start training at St. Mungo’s once he finished school. And then there was, of course, the triwizard tournament.

“Are you going to throw your name in?”

John looked up and tilted his head at Sherlock. “I don’t know. Maybe. I mean, I still have a month to decide, right? First of all I want to make sure that I pass my N.E.W.T.s.”

“I don’t want you to go. It is stupid and idiotic. Do you even know how high the chances of death in this tournament are?”

“Okay. I won’t throw my name in, then.”

“Good. Now, for Potions you can just give me your book, I'll go through it until the end of next week and then I'll ask Flitwick if there’s somewhere we can practice. He likes you, so it should be easy. And then we’ll see what we can do about Transfigurations. Also, that Thompson girl from Hufflepuff has a crush on me so I'm sure she’ll help you if I ask her.”

“Sherlock!”

“What?”

John shook his head. “You can’t just use her like that! She may have a crush on you, but it’s not okay to ask her to do things for you.”

“Fine, I'll ask someone else.” Sherlock rolled his eyes and pelted a piece of egg at John.

Somehow it didn’t surprise Sherlock that the Potter boy managed to get in trouble again, and he quickly lost interest in the tournament. That was, until winter came closer and everyone started talking about the Yule ball. Sherlock loved dancing and was good at it, and as soon as his teachers saw that he was released from the tedious lessons they were giving the students in a feeble attempt to make them look graceful at the ball. He spent the time experimenting instead and he found an interest in magical crimes and there were enough books about it in the library to last a lifetime.

He didn’t think much about the ball and whom to ask to go with him, he supposed he would find someone eventually. And if not, he was used to being alone and genuinely liked the absence of idiots. John, of course, had his eyes on a pretty girl in his year, and he eventually asked her our after dancing with her a few times during the lessons. She said yes, and Sherlock did his best to be nice to her.

Sherlock had hoped to avoid the conversation altogether, but it came as he had anticipated. Jessica Thompson, the Hufflepuff girl with a crush on him, asked Sherlock out. Remembering John’s warning to be nice to her, politely pointed out that he generally wasn’t interested in girls, and told her that instead she should ask Davon Colman, who was obviously interested in her since year four.

“Hey there.”

Sherlock was lying on a sofa in the common room with his face in a copy of “A Summary of Great Wizarding Crimes”, and glanced up to see Scott Estridge, the ginger haired sixth year Ravenclaw prefect. Slightly annoyed that he was disturbed, Sherlock merely raised an eyebrow at him.

“I overhear your conversation with that Hufflepuff girl last week,” the older teen began, and Sherlock squinted at him, going into full deduction mode.

“While you are good at all subjects that require learning, you are horrible at Divination and Alchemy – the latter is obvious, you should get rid of the stains on your robes – and you’re afraid to fail those classes. Furthermore, you are already torn between focussing on the study of magical creatures and following your father’s footsteps and working at the ministry after your N.E.W.T.s. Jessica asked me out after Potions, and usually there are no sixth year students around, which means you were probably following me. Furthermore, you only ever felt attraction to boys, and the reason you chose my conversation with her as a conversation starter is– Oh.”

Scott seemed like he couldn’t decide between getting angry and being impressed. “Yeah. I wanted to ask you out for the Yule ball. Sorry to bother you. By the way, that was impressive what you just did. Spot on.”

Sherlock blushed, not really having expected anyone to ask him out, and especially not a prefect. “Uhm, I mean, I’d love to. Sorry about that, it’s mostly automatic. But I mean, if you’re still interested I’d love to go to the Yule Ball with you.”

The redhead grinned at him. “It’s a date, then. I look forward to dancing with you.”

When Sherlock told John about it the next day, John was oddly quiet. Sherlock hoped it was more because of his Charms exam the following day rather than Sherlock’s date.

The day of the ball finally came and Sherlock made sure that he looked good in the new dress robe Mycroft had sent. He had agreed with Scott that they’d wear matching bowties and when Sherlock came downstairs to the common room, Scott was already waiting for him with a smirk on his face.

The evening was incredible, Scott was a really good dancer as well and Sherlock allowed himself to get lost in the twirl on the dance floor, not noticing the way John looked at him. It wasn’t until John’s date left, secretly annoyed that John didn’t pay much attention to her. Then John came over and tapped Scott lightly on the shoulder. Sherlock beamed at him, telling the blond how much he enjoyed that evening as they danced across the mostly empty room. John just hummed, and after a while Sherlock gave up and stopped talking. John was warm and comfortable and when a slower song came on Sherlock wrapped his arms around John’s neck and leant his head on John’s shoulder.

No matter how nice Scott was, it felt ten times better to dance with John, and there it was again, the fuzzy feeling in his stomach that had been there every time he looked at John since the sleepover night. And as if that was the missing piece, it suddenly clicked for Sherlock: He was utterly, heartbreakingly, irrationally in love with John. And John liked girls.

John could feel Sherlock stiffen against him and he stopped to look at the younger boy, placing a finger under Sherlock’s chin and tilting his head up.

“Sherlock, what’s wrong?”

Sherlock shook his head and gently pried John’s hands away from him, mumbling something about going back to Scott.

 

The following year was exciting for John and incredibly tedious for Sherlock. He didn’t really know what to make of the Potter kid’s claims that Voldemort was back, he was rather indifferent to it, but the new teacher for Defence against the Dark Arts was incredibly tedious and boring with her pink clothes and shrill voice. Sherlock had a couple of dates with Scott that year, but eventually they stopped and Sherlock was all alone again.

He wrote John at least once a week, and sometimes John sent him pictures of interesting wounds back with his letters, whenever he was allowed to take them. Umbridge had a penchant for rules and Sherlock got in trouble often for going out at night to collect samples. He tried to hide the “I shall not disobey” etched into his skin from John and his family when he came home that winter, but that was impossible.

“Sherlock, what the hell? Who would do such a thing?” John was obviously angry, and Sherlock tried not to flinch at his outburst. John just shook his head at him and began rummaging in his bag for some potions and a self-disinfecting bandage. He took care of Sherlock’s arm in silence and then pulled him into his arms, holding him close and planting kisses on Sherlock’s mop of curls.

It was better after that, he was no longer called into Umbridge’s office and Sherlock suspected that John told Mycroft about, who had somehow managed to get a good job in the ministry over the past six years. Sherlock often thought about John holding him and kissing his head.

 

It was a beautiful summer day and Sherlock and John were lazing around at the pond; John was taking a break from his training at St. Mungo’s and Sherlock was generally enjoying himself now that he was done with school. He didn’t really know what to do now, but he considered going to a muggle university to learn more about Chemistry. John had gotten him a bunch of books that explained it and it certainly seemed interesting. It was a bit like Alchemy and Sherlock had enjoyed that a lot in school, it was one of the subjects he had gotten an O in. His last year in school had passed quickly and for the most part without any events, until the headmaster died at the hand of death eaters who had invaded the school. There was something dark coming very soon and everyone could feel it, was nervous about it and tried to ignore it at the same time. There had been a lot of cases of unforgivable curses at the hospital lately and John had decided that they’d have to improve their defence spells, so that was what they were doing most of the summer, practicing counter curses and protection spells while sunbathing in their swimming trunks. They had even managed to cast Patroni, formless at first but soon enough Sherlock’s Patronus resembled a fox and John soon followed with a Patronus in the form of a German Shepherd They had figured out how to use them to send messages as well, and now their nights were filled hushed conversations in the form of pure light.

Sherlock looked over at John, taking in his muscular build (John had started to play Quidditch for the Hospital team and the effects were more than positive) and the way the small droplets of water on his skin made it glisten. John turned his head to meet Sherlock’s eyes and quicksilver blue eyes met brown ones. Sherlock wanted to look away but John’s searching eyes pinned him where he was, unable to move.

“You know, I never got a proper answer from you,” John said, and his voice had a certain edge that made Sherlock curious, something inside him moving at the sound. “You never told me why you left so suddenly at the Yule ball. I’ve been waiting the entire night to dance with you, my date left early because I didn’t pay attention to her, and then you left with such a feeble excuse.” John rose to his knees and crawled over to Sherlock, straddling the younger teen’s legs. Sherlock’s breath hitched and he licked his lips, still looking at John, unable to move or to say anything. “Tell me, how was your relationship with Scott? It didn’t really last long, did it? Tell me why it didn’t, Sherlock.”

And by Merlin, Sherlock didn’t care if this was just a trick to get him to admit it, Sherlock couldn’t keep it in anymore, not with the cascade of butterflies in his stomach and the way his heart pounded in his ears. “Because I was in love with you,” he blurted out. “Still am.”

And John just smirked, bloody smirked, and leant down to kiss Sherlock leisurely, leaving no doubt about how much he liked Sherlock.

Things improved exponentially between them. Sherlock found that it was much easier to ignore the feelings he had for John when he didn’t have to, and it felt good to be able to tell John how he felt on a regular basis. The sex was nice as well, especially because they took their time with exploring the possibilities. John went back to London and Sherlock visited him often, sneaking into university lectures every once in a while. He wished he could apply and make a proper degree, but with the current situation in the ministry he would only get in trouble for mixing with muggles. His mother understood, thankfully, and when he found an alchemist who was willing to teach him more he accepted.

The situation in the entire British Isles, however, didn’t improve. Voldemort was back in power and the new ministry of magic was his puppet, releasing law after law that made it illegal to be muggle-born. Muggles vanished from the streets, and every wizard and witch new that it was the work of the death Eaters who now had free reign. And then they attacked Hogwarts.

It was dawn when John suddenly appeared in Sherlock’s room, looking visibly shaken. He muttered something about Harriet and Hogwarts and danger, but Sherlock understood. He changed quickly and packed a few exploding potions he had learnt to make and grasped John’s hand, silently telling him that he was ready to go. They managed to bring Harriet safe to Silverkeep, and John’s father brought his wife and daughter away before joining the battle as well, a loyal Hufflepuff like his son. It was exhausting and they were mostly outmatched, but things started to look good the darker it got. They already began to hope, and then it happened. Sherlock saw everything as if someone had slowed down time: the green light of the killing curse aimed at John, the way John looked at him as if to apologise, and then John’s father who jumped in before John, taking the whole impact of the curse on himself. And then John screamed, and time seemed to snap back to its normal speed.

Sherlock was at his side in an instant after cursing the death eater who had wanted to kill John and tried to pull John away from the corpse. Everything that happened after that was muted, John’s eyes hardened in a way Sherlock had never seen before and he was afraid that they would completely soften. They carried John’s father into the great hall together and continued fighting, until it was bright morning and Harry Potter finally killed Voldemort.


	3. Crucio

John was understandably solemn after his father’s death, and Sherlock tried to help him in every way he could. Harry finished her last year at school and then began to work in the ministry. John didn’t continue his healer training right away, it took him a while to adjust back. The blond had also developed a limp, but he refused to let a healer look at his leg. Sherlock missed the old John, the John who would wake up every day with a smile on his face and a positive outlook on his life. The new John rarely smiled anymore, but Sherlock tried his best to change that.

But eventually things changed and the old John came back, even though he never completely lost that harshness in his eyes that made him looks so much older. He picked his training back up after a year and Sherlock moved in with him, beginning his Chemistry studies at a University there. John began to smile more often and Sherlock smiled with him, happy to have his John back. And for a while everything seemed perfect.

The first few times John came home drunk Sherlock didn’t pay attention to it, there had been a Quidditch game and John went to a pub in Diagon Alley with the other healers in training, nothing to worry about. Then, when it became a more regular occurrence, Sherlock shook his head at him, he didn’t really like it when John was drunk, the blond was always looking for a fight when drunk and Sherlock couldn’t stand the smell of firewhisky on John’s breath. When John came home one night and started throwing curses and hexes around, Sherlock couldn’t lie to himself any longer: John had developed a drinking problem, just like his sister. Sherlock knew that he should probably leave John, but he was determined that he could fix the blond, and John had never raised his wand at him.

Sherlock’s descend into addiction followed a similar pattern, even though he liked to pretend that he was in control of it. It started harmlessly, a girl in his biochemistry class in his second year suggested him to try it while they were working on a partner project, and from then on it was a downhill slope. He stayed away from home for several nights every once in a while and he’d come back fidgeting, craving his next hit. If John noticed, he didn’t say anything, they just pretended not to see each other’s problems. But situations like that never ended well and it came as it had to come.

Sherlock came home high as a kite, where John, obviously drunk, was already waiting for him they started arguing, and then they started shouting, and then they pulled their wands.

“What do you think you’re doing with your life, Sherlock?”

“You’re one to talk. You are the one who made me try it in the first place, you and your absence and your drinking.”

“I was coping, Sherlock! My dad died because of me and I didn’t want to burden you with my problems!”

“Well, you hurt me with your drinking. Don’t you see what it did to you? You are not the John I fell in love with anymore”

“Don’t play the innocence card. You were supposed to help me, not to hurt me further! Don’t you think I recognise track marks and the symptoms of drug abuse? I am not stupid!”

“Oh, shut up, John. Just shut up! It’s not my fault that you can’t deal with your father’s death! You are pathetic!”

“Crucio!”

Sherlock was shocked for a split second, staring at John in disbelief, before his entire body shook with the pain of all his bones being broken at once while being boiled alive. It didn’t last long, just a few seconds, but it still happened. John had tortured him with a flick of his wand.

“Oh, Merlin. I am so sorry, Sherlock.”

Sherlock groaned, curled into a foetal position on the floor. “Leave.”

And leave John did. He quickly sent a patronus to the hospital so that they could take care of Sherlock and threw a few clothes into a suitcase. He stayed in a motel for a few nights before breaking his wand in half and joining the army with a few magically forged papers. He stopped drinking that night.

The army did him good, and after a while John began to feel like himself again, the old self. He told them that he was trained as a nurse and they offered him full medical training, and soon he was out in Afghanistan, not using his magic at all and instead rescuing those wounded in the battlefield. He was admittedly reckless and didn’t really care if he died on the field. It earned him the rank of captain within two years. It also earned him a bullet in his shoulder and sent him home.

 

“John, wait!” Sherlock’s familiar voice, but much deeper now that he was in thirties. John tried to march faster, but his damned leg was hurting again. “John.” A hand on his shoulder. John turned around, automatically standing parade, forcing himself to look at Sherlock. The other man looked like he was about to cry, and Sherlock never was the sort to cry openly. Suddenly Sherlock wrapped his arms around him, pulling John close to himself. “When I told you to leave, I didn’t mean forever. I was worried. I didn’t know where you went until Mycroft told me you joined the muggle army.”

John used their closeness to stick his cane between his and Sherlock’s leg and hugged Sherlock back. He had missed this, had missed how Sherlock felt when he was so close, their bodies fitting perfectly together. “I'm so sorry, Sherlock. What I did was unforgivable. Literally. You were right, I was pathetic and drunk and I can’t believe I did that. I missed you so much.”

“Later,” Sherlock mumbled, pulling back and planting a kiss on John’s forehead with a small smile. He entwined their fingers and hailed them a cab to what John supposed was Sherlock’s new flat. It was beautiful and John swelled with pride. Sherlock told him that the landlady was a squib and that he had been able to prove her husband guilty of murder. He also must have told her about John, because she greeted him with a condescending look that said “don’t you dare hurt him again”.

The next morning, John woke up in Sherlock’s bed, one arm wrapped around Sherlock, who was warm and sleeping peacefully next to him. They had a serious conversation over breakfast where they put down sensible, general rules that were much needed so that they could do this, and then they went to John’s bedsit to get his stuff, and then they went to Ollivander’s to repair John’s wand.

They were sitting at home (John couldn’t quite believe his luck, but Sherlock would always feel like home) when a Detective Inspector came and started talking about suicides.

“Okay, you've got questions.” They were sitting in a cab on their way to somewhere, after Sherlock had been excited about a suicide.

“Yeah. Where are we going?”

“Crime scene. Next?”

On their way to a crime scene, then. “So what exactly do you do now?”

“What do you think?” Sherlock smirked. John wondered how the man had managed to become even more handsome.

“I'd say private detective.”

“But?”

“But wizards don’t work as private detectives. They are aurors.”

“They don’t join the muggle army either, but here you are. I'm a consulting detective, the only one in the world. I invented the job.”

“What does that mean?”

“It means whenever the police are out of their depth—which is always, and especially when it seems like a wizard or witch did it—they consult me.”

John killed a man that night for Sherlock (with the gun from the army) after chasing him through London. As Sherlock suspected, the man used the Imperius curse on his victims, forcing them to take a poisoned pill to make it look like a suicide. John didn’t feel a hint of remorse shooting him. And it felt like it was at least setting some things right again. They had a lot to work out, but at least they were on the right path.

“Dinner?”

“Starving.”

**Author's Note:**

> I really hope you enjoyed this, and feel free to tell me so in the comments!  
> Also thanks to Charlie for going over this and correcting things, and to the entire Team Fuck Sleep for encouraging me and telling me to get off tumblr.  
> And of course thank you, theconsultingpanda, for participating in this.


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